In recent years, there have been solid-state imaging devices that have focus detecting pixels as well as imaging pixels in the pixel array unit, and detect a focal point based on a shift amount between signals output from a pair of focus detecting pixels, or conduct focus detection of a so-called imaging-plane phase difference AF (Auto Focus) type.
Among such solid-state imaging devices, various techniques have been suggested so as to optimize the respective sensitivities of the imaging pixels and the focus detecting pixels.
For example, a solid-state imaging device in which one microlens is placed to cover more than one focus detecting pixel has been suggested (see Patent Document 1, for example).
Also, a solid-state imaging device in which the microlenses of imaging pixels and focus detecting pixels having different refractive indexes are formed in the same layer has been suggested (see Patent Document 2, for example).
Further, a solid-state imaging device in which in-layer lenses are provided only for the focus detecting pixels has been suggested (see Patent Document 3, for example).